1. Field of Invention
The inventive concepts disclosed and claimed herein relate generally to a pigment composition for paper laminate and, more particularly, but not by way of limitation, to particulate pigment attached to carrier particles, wherein colloidal spacer particles are present on the pigment particle surface, and process for surface treating particulate pigment, colloidal particles and carrier particles to produce the carrier particles having pigment composition.
2. Background of the Invention
Particulate inorganic pigments are used as opacifiers and colorants in many industries, including the coatings, plastics, and paper industries. In particular, titanium dioxide pigments, generally in the form of finely divided powders, are added to a pigmented paper laminate or décor paper to impart the desired level of opacity.
Paper laminates are well known in the art and are suitable for a number of uses such as table tops, wall panels, floor surfacing and the like. The paper laminates are produced by impregnating paper with a resin(s) and pressing the impregnated papers which are stacked on top of each other. The type of resin and laminate paper are dictated by the end use of the laminate. Decorative paper laminates can be made by using a decorated paper layer as the upper layer. The decorative paper base differs from the usual types of paper in that the pulps used are very white/bright, and the décor paper has a high proportion of pigments and fillers to achieve the desired high opacity.
When making pigmented paper laminate or décor paper using existing commercial products, the manufacturer has two problematic issues. Firstly, a significant amount of the pigment fails to retain within the paper fiber lattice, requiring additional processing steps to recover the pigment. Secondly, the pigment particles become extremely flocculated, thus requiring high levels to impart the desired level of opacity from the paper.
Light scattering, stability, brightness and opacity of a pigment can be limited at high pigment concentrations due to flocculation or to an effect known as crowding. In paper products, one way to keep the pigment particles spaced at an optimum distance is by adding spacer particles. While there has been some research regarding the proper size and shape of spacer particles, there remains a need for improved compositions and methods for making spaced titanium dioxide pigments having minimal flocculation and improved opacity in paper laminates.
Improved retention technologies have typically focused on use of additives to the paper fiber/pigment furnish. There further remains a need for compositions and methods for making spaced titanium dioxide pigments that deliver improved retention when used in paper laminate.